Beet juice: it’s the nitrates, stupid


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- Alex Hutchinson (@sweatscience)


More research from Andrew Jones’s group at the University of Exeter on the endurance-boosting effects of beet juice, which they previously reported can extend time-to-exhaustion by about 15% (equivalent to about a 1% improvement in a race over a specific distance), in a forthcoming paper in the Journal of Applied Physiology (press release here).

The most interesting new twist: they’ve developed a way of filtering the nitrates out of beet juice using an “ion-exchange resin,” allowing them to create a placebo form of beet juice that is identical to the real thing in every way except for the absence of nitrates. They’ve hypothesized that it’s the nitrate in beet juice that reduces the “oxygen cost” of running and other endurance exercise — i.e. you burn less energy to produce the muscular force needed to propel yourself forward, allowing you to last longer. But beet juice has a whole bunch of potentially beneficial ingredients, including big names like quercetin and resveratrol, so they needed some way to check which ingredient was actually making the difference. The new double-blinded study does that nicely: the nitrate-free beet juice had no effect on subjects, while the regular beet juice lowered blood pressure and improved performance in various endurance running tests.

One other new result is that they tested low-intensity exercise as well as high-intensity. Sure enough, they found that the oxygen cost of walking was significantly decreased after just four days of drinking 500 ml of beet juice per day.

For senescent populations or individuals with pulmonary, cardiovascular or metabolic disorders, [they write,] a reduction in the O2 cost of daily activities might significantly improve functional capacity.

Maybe, maybe not — I’m not convinced seniors will really care about shaving 1% from their evening walk time. But for competitive athletes, the body of evidence for beet juice is getting solid enough to make me reconsider my initial skepticism. I’d like to see similar results from other labs, though.

23 Replies to “Beet juice: it’s the nitrates, stupid”

  1. Not scientific, but MMA star Urijah Faber drinks beet juice throughout training and he’s known for his endurance.

  2. I’d think so — but the issue is whether you could eat enough beets to get the same amount of nitrate. In the study, the subject were drinking two cups (500 ml) of beet juice a day. I don’t know how many beets it takes to make two cups of juice, but I’m betting it’s a surprisingly large number! (The 500ml of juice contained a total of 6.2 mmol on nitrate, which works out to around 384 grams. But I can’t find good data on nitrate content for beets.)

  3. Nitrate content is hard to come by. I found some sources awhile back but don’t have them bookmarked. In addition to beets both spinach and celery are very high. I’m not big on supplements but anecdotaly my endurance does seem improved when I am including these 3 sources in my diet on a daily basis.

  4. The legal norm for nitrate in beetroot in my country (The Netherlands) is 4000 mg/kg if harvested from april to july and 3500 mg/kg if harvested from july to april. If my calculation is correct*, you’d need about 85g of ‘barely legal’ beetroot of 4000 mg/kg.

    Of course, the average amount of nitrate may just as well be 1/100th or 1/1000th of the legal maximum, so 85g would be an absolute minimum.

    *) 1 mol NO3 = 62g , so 5.5 mmol NO3 =0.341g. If 1 kg of beetroot contains 4 g, 0.085kg contains 0,340g of nitrate

  5. @RH

    Thanks for that data, RH — your calculation looks good to me (though I hope all this talk about “barely legal” doesn’t get my blog banned!) 🙂

    The fact that nitrate levels vary so much (depending on the local water supply, fertilizer choice, time of harvest and so on) would make it complicated. Still, I guess the study used beet juice for just a few days to observe the effect, so it’s not like you’d have to eat that many beets every day of the year — just leading up to competition.

    Ultimately, given all the excitement around this research, I’m assuming that nitrate supplements will become popular — thus eliminating all the worries about purple pee…

  6. Alex:

    If someone was training for a marathon, would it be better to drink beet juice every day, or just in the days immediately prior to the event?

  7. @Steve
    I think the jury’s still out on that one. The studies suggest that you can get a boost from doing it just before the marathon. On the other hand, if you do it throughout your build-up, you’d presumably manage to train at a higher level.

    Given that there are still some questions about the health effects of high levels of nitrates (see the pponline article I linked to in a comment above), I’d be inclined to try it for relatively short periods of time before key races. Ideally, that helps you avoid getting absolutely fed up with beets, and maximizes the psychological/placebo effect as well.

  8. This is great information. But, If I were to drink half of litre of beet juice a day I would fall into a major depression. For the past five years I have been juicing, and have not experienced any negative effects from any fruit or vegetable except beets. There is no doubt in my mind that drinking beet juice (mind you only half of beet per day) causes negative feelings, such as depression, resentments and regrets. So the question I have (for anyone out there) is: Is there any scientific data ( I couldn’t find any) that shows drinking beet juice causes depression. By the way, I have no tendency to be depressed or to have any other psychological disorder.

  9. @Mary
    Wow, that’s not something I’ve encountered before. I did a quick search on Pubmed, but couldn’t find anything relevant. Anyone else have any leads?

  10. The side effects of several medicinal nitrates (e.g. isodril) include restlesness and tiredness (but not depression). I don’t know if these substances are comparable to dietary nitrate, and side effects of drugsare usually not particularly well researched, but perhaps it is a clue.

  11. I remember reading about nitrates and nitrites in The Omnivore’s Dilemna particularly as a biproduct of pesticide use. They leached into the ground water and when they were at a certain level in the river in Des Moines (I think) they issued “blue baby” alerts. Apparently children died when their oxygen level was compromised by the nitrites in the water. This is all very foggy – I realize – but I’m curious about how nitrates in beet juice are beneficial when they are not at all so in processed meats and/or as a bi-product of pesticides…???

  12. I have used beet juice for cleansing the blood stream for almost 10 years now. As long as you stick to the recommended dosage I have not had any problems with side effects. I use RediBeets which is produced by a company in Idaho. It’s concentrated beet juice and the powder makes dosing easier to be sure you’re only getting what you intend to intake.

  13. @Mary
    Mary, How can you conclusively prove that beet juice caused your alleged depression? It seems every site i go to to collect information, theyre are naysayers that GIVE OUT WARNINGS, for anything that is healthy for 99.99999 % of the population. Yet theyre WARNINGS OR BEWARES, cause many people unnecessary Caution. BEWARE OF BANANAS ! you mite slip on the peel! Bananas are Dangerous ! Juice a Beet, Chill, & Drink. But BEWARE OF BANANAS!

  14. My interest is piqued enough that I have a question… Does the powdered/capsule form supply the same benefit as drinking the juice? I am always a bit wary of additional processing, but do find the thought of a capsule more palatable and convenient than buying and drinking the juice.

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